Textile crimping



Aug. 26, 1969 D. A. Ross TEXTILE CRIMPING 4 Sheets-Sheet 1 Filed Aug. 16. 1967 INVENTOE; I

DONALD ALEXANDER ROSS b M r ram/Ers- Aug. 26, 1969 D. A. Ross 3,462,312

v TEXTILE cnmrme Filed Aug. 16, 1967 4 Sheets-Sheet. 2

INVENTOR DONALD ALEXANDER Ross WWW A TTORNE Y5 Aug. 26, D. A. ROSS 4 TEXTILEQCRIMPING Filed Aug. 16. 1967 4 Sheets-Sheet 5 INVENTOR, DONALD ALEXANDER ROSS ATTORNEYS Aug. 26 1969 D. A. ROSS 3,462,312

TEXTILE CRIMPING Filed Aug. 16, 1967 4 Sheets-$heet L INVENTOR, DONALD ALEXANDER ROSS lay MW Zrmmvsrs United States Patent Ofifice 3,462,812 Patented Aug. 26, 1969 U.S. 'Cl. 281.6 8 Claims ABSTRACT OF THE DISCLOSURE Textile fibres are folded by continuously holding and advancing unfolded fibres, for example in the form of a sliver, into a small folding zone and continuously holding and conveying the folded fibres at a lower speed away from the folding zone, between a pair of spaced surfaces, the folding zone being so small that the strand of fibres is folded at the intake to the spaced surfaces into simple folds or waves having an amplitude determined by the spacing between the spaced surfaces. The folds can be set to provide a permanent crimp. The method avoids excessive back pressure and consequent fibre damage, and is therefore valuable for fibres such as Wool. The invention also provides a folding device specially adapted to carrying out the above method. However, it has also been found that this device can be used to treat yarn, and thereby achieve new properties and effects which are quite different from the properties of yarns made up from fibres crimped by the method described herein, or the effects achieved in treating slivers of fibres.

The present invention relates to the mechanical folding of textile fibres into corrugated form, and more particularly, but not exclusively, to folding of textile fibres that have relatively low tensile strength, such as wool.

In a known method of crimping textile fibres a strand of fibres is fed into a crimping chamber at a greater rate than they are withdrawn from the chamber. A packed mass of fibres builds up in the chamber, and the incoming strand of fibres encounters a considerable back pressure as it is forced against the mass of fibres, and is thereby compacted and crimped, the fibres being set in the crimped condition. Devices that use this method for crimping fibres are known as stulfer box crimpers.

Stuffer box crimpers are usually used for the crimping of synthetic yarns and filaments that are much stronger than wool fibres. If stulfer box crimpers are used to crimp Wool fibres, damage is caused to the wool fibres and their tensile strength is considerably reduced.

It is the principal object of the present invention to provide a method and apparatus for the crimping of textile fibres, which is particularly suitable for fibres of low mechanical strength, such as wool.

The method according to the present invention comprises continuously holding and advancing an unfolded strand or layer of textile fibres at a first speed to a folding zone and continuously holding and conveying the folded strand or layer between a pair of spaced surfaces away from the folding zone at a second speed slower than the first, the location of release of the unfolded strand or layer being so close to the spaced surfaces, and the folding zone being thereby so small, that the strand or layer is folded at their entry between the spaced surfaces into simple folds or waves having an amplitude determined by the spacing between the spaced surfaces, the second speed being related to the first speed in accordance with the amplitude and pitch of the folds or waves. If the folded strand is then conveyed through a setting zone where the fibres are set in the folded condition, permanently or substantially permanently crimped fibres can be obtained.

In the preferred embodiments of this method, the unfolded strand or layer is itself closely confined between a pair of parallel surfaces, and the strand or layer may be advanced before folding or conveyed after folding, or preferably both, by movement of at least one of the appropriate surfaces.

Although the invention has some application to fibrous strands and layers of various forms, it is particularly advantageous when applied to a flat sliver of fibres. When a sliver of fibres is treated by the method just defined, it is folded into a corrugated wave form and, since the back pressure on the sliver from the folded portions further ahead can be kept to a minimum little fibre damage need be incurred. A fundamental difference between this meth- 0d of crimping and that of the stuifer box is indicated by the form of crimp imparted.

The product of the present invention has novel charac teristics which distinguish it from the products of prior crimping processes and devices, and more especially from fibres crimped in stuffer box crimpers. Fibres folded in accordance with the invention exhibit a regular wave form with rounded wave crests. The individual fibres may not be crimped in one plane only but may be folded in a three dimensional conformation or into three dimensional helices. Fibres crimped in stuffer boxes, on the other hand, are irregularly crimped and have sharp angles separated by straight leg lengths, and it is at the sharp angles where damage occurs.

The form of crimp and possible fibre damage imparted by stutfer box crimpers are due to the compacting of the fibres against the back pressure in the confined space of the stulfer box. To build up this back pressure it is necessary that the stuifer box should be confined on all four sides. In contract to this, no confining side walls are necessary with the present invention, either in the folding zone or subsequently. Indeed, it is preferable that no side walls be employed, because it is then possible to pass slivers or laps of various widths through the same machine.

For a given spacing of the pair of spaced or conveying surfaces, there is a maximum permissible distance between the point of release of the unfolded fibres and their entry in a folded condition between the spaced surfaces, beyond which the strand or layer will deviate from its general direction of movement to such an extent that complex and irregular folding occurs, and the form of the product will then begin to resemble that characteristic of stuffer box crimpers. This maximum permissible distance, or maximum length of folding zone, varies with the spacing of the spaced conveying surfaces-the greater the spacing, the greater the permissible distance and is most conveniently determined by experiment and visual observation in a given case. It can thus readily be arranged that, with the desired spacing of the conveying surfaces, the folding zone is sufficiently short for the fibre strand or layer to fold into simple folds in the manner described above.

It has moreover been observed that, in apparatus engaged in folding fibres in accordance with the invention, the distance apart of the conveying surfaces and the distance between the location of release of the fibres from the feed surfaces and the intake between the spaced surfaces holding the folded strand, which distances effectively define the height and length respectively of the folding zone, are of the same order of magnitude as each other and as the ampltiude of the folds or waves produced.

For a given amplitude, the pitch of the folds or waves, that is to say the distance from one peak to the next in the folded material, is principally determined by the ratio between the speeds of advance of the unfolded strand or layer and conveyance of the folded material.

The invention also provides a device for carrying out the invention, which comprises at least one feed belt cooperating with a substantially parallel opposed surface for holding and advancing an unfolded strand or layer of textile fibres, at least one conveyor belt cooperating with and spaced a predetermined distance from an opposed surface for holding and conveying a folded strand or layer, and means for driving the feed belt at a higher surface speed than the conveyor belt, the output end of the feed belt being so closely adjacent to the intake end of the conveyor belt that a fibre strand or layer passing from the one belt to the other will become folded into substantially simple folds or waves having an amplitude determined by the predetermined spacing between the conveyor belt and the cooperating surface opposed thereto.

In such an apparatus, a single feed belt may cooperate with a stationary plate or a pair of substantially parallel, closely spaced, similarly moving feed belts may be employed. Similarly, the conveyor belt may cooperate with a stationary plate, which may be coplanar with or a continuation of a stationary feed plate, but a pair of parallel, similarly moving conveyor belts is preferred. The feed belt and the stationary plate, or the pair of feed belts, as the case may be, diverge at a position as close as possible to the intake of the pair of conveyor belts. A convenient way of arranging this is for the feed belt or belts to be readily flexible and to pass at the output end over a guide or guides of small radius of curvature, which enables the output end of the feed system to be introduced close to the intake of the conveyor belts, for example where the latter pass over rollers or guides of arcuate profile whether of small or of relatively large radius of curvature.

The fibres may be set in their crimped condition while confined between the pair of conveyor belts. In the case of synthetic fibres, the fibres may be folded in the heated condition, and may merely require to be cooled. Fluid setting agents can be applied through the feed or conveyor belts, where these are permeable. Where wool is to be crimped, steam is often employed for the purpose of setting the crimp with or without treatment of the wool with a setting reagent, and for this purpose the conveyor belts may be permeable and pass through a steam chamber. Provision may also be made for applying steam to the sliver before it is crimped, in order to condition it for the folding operation. Setting agents may be applied to the Wool at any stage before steaming is complete, either by spraying on to the fibres while they are confined between permeable belts, by padding the sliver in a solution of the reagent before it enters the crimping device, or by any other convenient means.

With the method and device according to the invention, as contrasted with stutfer box crimpers, control of the dimensions of the imparted crimp is relatively easy. The level of crimp can be conveniently defined in terms .4 of two factors, namely, the crimp frequency which is the number of crimp waves per unit length of crimped sliver, and crimp height. In a stutter box crimper the level of crimp is determined by the back pressure of the crimped fibre mass in the crimping chamber, and these factors are not easily controlled independently.

In considering crimp height and crimp frequency, it must be understood that the crimp height and frequency of individual fibres taken from a set, crimped sliver in accordance with the invention is not necessarily the same as the crimp height and frequency of the crimped sliver as such. Moreover, the crimp height and frequency of a set, crimped sliver must be distinguished from the amplitude and pitch of the folds initially imparted to the sliver, as discussed above. The relationship between the dimensions of the initial folds and that of the final set crimp, depends on the efiiciency of the setting operations on the fibres concerned.

Nevertheless, it remains true that in crimping fibres in accordance with the invention, the height of the crimp can be controlled directly by the spacing of the conveyor surfaces. Thus in the preferred apparatus, the crimp height of the sliver is increased by increasing the distance between the conveyor belts, and is decreased by decreasing this distance. As the crimp height increases, the crimp frequency decreases. However, at a given belt spacing, crimp frequency can be controlled by the relative speeds with which the sliver is advanced and conveyed on opposite sides of the folding zone, namely by the ratio of the feed belt speed to the conveyor belt speed, which may be termed the feed ratio. As this ratio is increased, with a given spacing of the conveyor belts, more crimps of the same height are formed per unit length of crimp sliver. The level of crimp in the sliver may easily be altered while the machine is in motion by altering the feed ratio or the belt gap so as to provide variably crimped sliver.

This control is particularly easy to effect with feed ratios within the range of 2:1 to 8: 1. Where the feed ratio is less than 2: l, and the conveyor belts are almost in contact, or have a very small gap of, for example, 0.05 inch, a fiat crimp wave is formed. As the feed ratio is increased the back pressure on the sliver is increased, and at feed ratios of 8:1 or above sensitive fibres such as wool may suffer undesirable damage. With Wool fibres, the preferred feed ratios are between 3:1 and 6:1. It may be noted that the feed ratio in a given case is always higher than the ratio of the unfolded to folded sliver length. This is due to slippage between the sliver and the belts, which depends on the frictional characteristics of the belts and the sliver and the tension of a stationary feed plate, when used, against the sliver. As the feed ratio is increased, at a contsant conveyor belt speed, so the crimp frequency increases and the crimp angle decreases and the uncrimping" forces in the sliver increase. Where steam is employed to set wool fibres, the efiiciency of setting depends on the time of steaming and steaming time adequate at low feed ratios may be found inadequate at high feed ratios.

Other factors affecting the crimp produced arise from the nature and dimensions of the fibrous strand being folded. Other things being equal, a thick sliver gives a higher crimp height and frequency than a thin sliver. Flexible fibres are more readily crimped than less flexible, and thus with the same setting of the device and in slivers of equal weight, [Merino fibres exhibit greater crimp frequency than New Zealand Crossbred wool, which are of greater diameter.

In folding slivers of wool fibres, spacings of the spaced conveyor surfaces found most satisfactory are from 1 to 5 mm. However, in crimping yarns in the same apparatus, as described below, the preferred spacing is 1-3 mm.; at higher spacings the yarns tend to spread sideways and the desired effects are not achieved.

Apart from the conventional applications of crimping to fibres, for the purpose of increasing their resilience, compressibility, covering power or bulk or of enhancing their handle, a sliver crimped according to the invention can, by virtue of its accurately controlled height and frequency, be employed as a corrugated pile. Thus folded sliver may be attached to a backing fabric, for example by means of a latex adhesive, to form a looped pile carpet or furnishing fabric, or alternatively it can be bonded between two backing fabrics and subsequently cut to form two out pile fabrics. Another important application of the folding technique according to the invention is for imparting to slivers a temporary crimp to improve their processing properties.

A further important aspect of the present invention is the treatment of yarns in the apparatus defined and described above. Yarns so treated have very different properties from yarns made from crimped fibres.

The effect produced on yarn by a device according to the invention depends largely on the space available to the yarn as it leaves the feed belts or other feed surfaces, that is, in the folding zone. The available space is determined by the spacing of the conveyor surfaces, the feed ratio and the density of the yarn feed. If an individual yarn is fed, it can move freely sideways in the folding zone, but if many yarns are fed in together side by side, to form the equivalent of a dense sliver, the sideways movement of the yarn is restricted and the yarn will take up a different crimped form.

Simple crimped yarns (as illustrated in FIG. 6A) are produced by feeding many yarns together into the device at feed ratios of about 4:1 or above. In these conditions a ply yarn will act as a single entity, and the single plies will bear the same relationship to one another in the crimped yarn as they did before crimping. The packing factor of such crimped yarns will not be appreciably altered by the crimping process.

In contrast, if yarns are fed together but in a less dense feed, and at feed ratios less than 4: 1, the yarn may become compacted, decreasing in length and increasing in diameter, as illustrated in FIG. 6B. Individual plies of ply yarns may separate and form helices. The yarns may be halved in length, so doubling the tex count, and the packing factor may decrease by about 20%.

Singles or ply yarns may be treated in such a Way that the individual plies become separated and kinked, as illustrated in FIG. 6C. The occurrence of this effect is partly dependent on the level of ply twist in the yarn. Low twist yarns become kinked under conditions where high twist yarns are compacted.

Crimped yarns are easier to uncrimp than compacted yarns. As the feed ratio is increased the load required to uncrimp a given yarn decreases as the yarn passes from the compacted to the crimped form. There is some indication that compacted yarns are appreciably stronger than corresponding untreated yarns.

Yarns treated in the apparatus of this invention thus possess novel properties which make them of especial interest for certain end uses. For examples, they afford the possibility of new surface elfects in carpetsas the yarns become more compacted the carpet pile turns until it lies at right angles to the direction of tufting.

The invention will be further described by means of some examples of folding and crimping apparatus embodying the invention, reference being had to the accompanying drawings, in which:

FIG. 1 shows in diagrammatic form an apparatus for crimping fibres in accordance with the invention;

FIG. 2 is a detailed diagram showing the folding zone of the apparatus of FIG. 1;

FIG. 3 is a diagram showing the folding zone of an alternative form of device embodying the invention; and

FIGS. 4 and 5 are diagrams of systems by means of which sliver crimped in accordance with the invention can be directly applied to the manufacture of pile fabrics.

FIGS. 6A, 6B and 6C illustrate the effect of treating yarns in the apparatus according to the invention.

Referring first to FIGS. 1 and 2, a sliver 11, for example of wool fibres, is passed through the tensioning rollers 12 and then through an adjustable guide 15, and is advanced by a continuous feed belt 16 passing over an idle roller 17, a driving roller 18 and a guide roll 19 of small diameter, for example of 5 mm. diameter (see FIG. 2). The belt 16 cooperates with a fixed feed plate 20, which is spring loaded against the belt 16. As the sliver is advanced by the feed belt 16 it can, if desired, be treated with steam, which heats the fibres to about C. to facilitate their crimpings. The strand is then discharged from the feed belt 16 and plate 20 into the intake of a pair of spaced, porous conveyor belts 21 passing respectively over a pair of guide blocks 22 and 23 of arcuate profile, having for example a curvature of 2 mm. radius at 24 (see FIG. 2). The guide block 22 is adjustably mounted so that the spacing of the conveyor belts 21 can be varied at will. The block 22 may also be spring loaded in order that the belts should return to their predetermined spacing after any displacement which may occur during operation. The belts 21 pass additionally over guide rollers 25 and belt tensioners 26, and are driven by rollers 27 at a speed slower than that of the feed belt 16. The guide roll 19 and the end of the feed plate 20 are placed as close as possible to the guides 22 and 23, while avoiding actual contact between the feed belt, feed plate, and conveyor belts, to make the folding zone between the feed and conveying systems as small as possible.

The sliver 11 entering the folding zone becomes folded into a corrugated wave form in which it is held by the conveyor belts 21 while it is advanced through a steam box 28 and then through a drying box 29 heated by hot air from a heater 30, to temporarily set the crimp and dry the sliver. The crimped sliver 31 is then finally conveyed to a discharge point in the region where the conveyor belts 21 diverge. The drive roller 18 for the feed belt 16 is driven from a motor 32, and the drive rollers 27 for the conveyor belts 21 are driven from a motor 33, the speeds of the two belt systems being thus independently variable.

The level of crimp can be adjusted to suit differing materials by varying the relative or absolute speeds of the feed belt 16 and the conveyor belts 21 and the spacing of the latter as described above. When a sliver of wool fibres is treated in the apparatus of FIGS. 1 and 2 the feed ratio may lie between 1:1 and 10:1, while especially good results are obtained when the ratio is from 3:1 to 6:1.

Chemical agents for permanently setting the crimp can be used, such as an aqueous solution of an alkali metal or amine sulphite or bisulphite. Moreover, although the setting agent can be applied before the sliver 11 enters the folding device proper, it can also be applied during the passage of the sliver between the feed belt 16 and plate 20, or between the conveyor belts 21, provided the appropriate belts are porous.

A modified form of device is shown in FIG. 3, where the feed unit includes a pair of feed belts 16 and 16a, instead of one belt and a stationary plate as in FIGS. 1 and 2. The feed belts pass over driving rollers 18 and 18a and over guide rolls 19 and 19a of small diameter.

The conveyor belts 21 in this device demonstrate another possible variation, in that they pass over the large diameter rolls 34 and 35, the roll 34 being resiliently mounted and adjustable to vary the spacing of the belts 21.

Instead of being rollers, the guides for the feed belts can take the form of wedge-shaped members having a smooth surface around which the belts can slip, with an effective radius of curvature in the range of from 1 to 12 mm. and preferably between 3 and 6 mm.

Examples of the production of crimped slivers of various fibres by the process and apparatus of the invention are summarised in the table.

TABLE Crossbred Merino Acrylic Acrylic Viscose 50% wool/ 50% Wool/ Fibre W001 W001 Cotton (acrilan) (Courtelle) rayon 50% acrilan 50% Courtelle Quality No 46 64 Denier 5 6 4. 5 Fibre length (cm 15 13 15 Sliver weight (ktexlcm. feed) 0. G 1. 5 1. 1. Feed width (0111.) 14 14 5 12 12 Conveyor belt speed (em./min.) 80 100 80 80 80 so Conveyor belt spacing (nun.) 4. 0 2.0 2.0 2.0 2.0 2. 0 2.0 2.0 Feed ratio 6:1 4:1 6:1 6:1 6:1 6:1 6:1 6:1 Steaming time (see) 19 19 19 19 19 19 19 Drying time (see) 57 45 57 57 57 57 57 57 Crimps/cm. 3.8 3. 2 5. 6 4. 5 6. 5 5. 3 8.0 8 5 Crimp height (n1rn.) 5 2 3.1 6 3.5 2. 9 3.5 3. 7 3 7 Straight length/crimped length 4 9 3. 7 2. 6 2. 9 3. 6 3. 5 5. 3 5 4 first speed in accordance with the amplitude and pitch of the folds or waves.

The following is an example illustrating the advantage of the invention over the conventional stuffer box crimpi t h i 2. A method according to claim 1 in which the folded A 100% wool sliver was crimped in the apparatus de- Strand or layer is conveyed to a setting zone where the scribed herein, with a feed ratio of 6:1. Another 100% folds 0r Waves are set to produce set crimped fibres.

wool sliver was crimped in a conventional stuffer box 00 3. A method according to claim 2 in which the folds crimper under a roll pressure of 12 lb. and a heating of waves are set while the strand or layer is confined block temperature of 235 F. The breaking strength of between the pair of spaced surfaces which convey the the sample crimped in accordance with the invention was folded strand or layer from the folding zone. determined and expressed as a percentage of the breaking 4. A method according to claim 1 wherein the strand strength of the stuffer box product. The fibres crimped Or layer comprises keratinous fibres such as wool. in accordance with the invention showed a strength nearly 5. A method according to claim 4 wherein the spacing 300% that of the stuffer box product. between the spaced surfaces is from 1 to 5 mm.

The invention as specifically described is applicable to 6. A device for folding textile fibres comprising: a wide range of fibrous and filamentary textile materials at least one feed belt having an input and an output including synthetic fibres and filamentary materials such end; as nylon, cellulose acetate and polyethylene terephthalate, a feed surface opposed to and substantially parallel but it is particularly useful for the crimping of slivers of with said feed belt; animal fibres such as wool, which require careful treat- Said feed belt and feed surface cooperating to hold ment if their mechanical strength is not to be adversely and advance an unfolded strand or layer of textile aifected. fibres;

As mentioned above, the regular and controlled at least one conveyor belt having an intake and a discrimped configuration exhibited by the product of the charge end; present invention makes it suitable for the direct manua conveyor surface opposed to and spaced a predefacture of pile fabrics, and FIG. 4 illustrates one such termined distance from said conveyor belt; system. The crimped strand 24, or a traversely spaced said conveyor belt and conveyor surface cooperating array of such strands, emerging in a set condition from to hold and convey a folded strand or layer of fibres; the conveyor belts 21 is led onto the surface of a backmeans for driving the feed belt; ing fabric 36, which has previously been coated with latex and means for driving the conveyor belt at a lower adhesive. A looped pile fabric 37 is formed. Alternatively, surface speed than said feed belt; as illustrated in FIG. 5, the crimped strand 24 or array the output end of said feed belt being sufiiciently close of strands may be led between two lengths of backing to the intake end of said conveyor belt that a fibre fabric 38, the facing surfaces of which have previously strand or layer passing from said feed belt to said been coated with a latex adhesive. The laminated maconveyor belt will become folded into substantially terial 39 is passed through a latex curing zone 40 wheresimple folds or Waves having an amplitude deterafter a knife 41 cuts the crimped strands medially to dimined by said predetermined spacing. vide the laminate into two cut pile fabrics 42. 7. A device according to claim 6 in which the feed What is claimed is: belt passes round a guide at the output end thereof, which 1. A method of producing folded textile fibres which guide has a sufliciently small radius of curvature to encompreses continuously holding and advancing an unsure that the output of said feed belt is located closely folded strand or layer of textile fibres at a first speed to adjacent to the intake of said conveyor belt as aforesaid. a folding zone characterized in that the unfolded strand 8. A device according to claim 6 in which the conveyor or layer is held between a pair of parallel surfaces, and belt passes through a setting zone in which the fibres is advanced and conveyed by movement of at least one held therebetween can be treated to set the folds or waves of each pair of surfaces, continuously holding and conformed therein. veying the folded strand or layer between a pair of spaced References Cited surfaces away from the folding zone at a second speed UNITED STATES PATENTS slower than the first the location of release of the un- 2,500,690 3/1950 Lannan 2872 X folded strand or layer belng so close to the intake to 2,908,044 10/1959 Whitney the spaced surfaces, and the folding zone being thereby so small, that the strand or layer is folded at the intake to the spaced surfaces into simple folds or waves having LOUIS RIMRODT, Pnmary Exammer an amplitude determined by the spacing between the US, Cl, X R spaced surfaces, the second speed being related to the 2872.14

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 'MEIZ RIZ Dated Au t 26 19 Inventor g It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Claim 1, C01. 7, line 54, change "compreses" to --comprises--.

Claim 1, Col. 7, line 56, delete "characterized in that the unfolded strand".

Claim '1, Col. 7, lines 57 and S8, delete these lines in their entirety.

Claim 1, Col. 7, line 59, delete "of each pair of surfaces".

Claim 1, Col. 7, line 59, before "continuously" insert "and".

Claim 1, C01. 7, line 62, after "first" insert --characterized in that the unfolded strand or layer is held between a pair of parallel surfaces, and is advanced and conveyed by movement of at least one of each pair of surfaces--.

Signed and sealed this 17th day of August 1971 (SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting Officer Commissioner of Patents 

